Portable power-driven tool



Sept. 25, 1951 G. B. LARsoN PORTABLE POWER-DRIVEN TOOL Filed April 20, 1945 Patented Sept. 25, 1951 UNITED STATES PATENT OFFICE PORTABLE POWER-DRIVEN TOOL Gilbert B. Larson, Geneva, Ill., assigner to Independent Pneumatic Tool Company, Chicago, Ill., a corporation of Delaware Application April 20, 1945, Serial N; 589,424

3 Claims. (Cl. 81-54) This invention relates to improvements in valve controlling means for supplying motive uid to rotary impact and other portable power operated tools.

The principal object and purpose of my invention is to provide a valve control mechanism incorporated in the tool and operable in response to pressing the tool against the work to open the valve or condition it to immediately supply an increased amount of motive fluid to operate the tool motor to pick up the load impressed thereon.

A further object of my invention is to provide a controlrod or element for opening the valve and have said element located in or operate through or around the tool motor and the tool spindle.

A further object of my invention is to locate the valve to be operated by the rod either in oil'- set relation thereto or directly in line therewith.

A further object of my invention is to have the rod actuate the valve by the relative movement between the tool and the work engaging iixture at the front oi the tool.

A further object of my invention is to provide said valve controlling mechanism in conjunction with the regular starting and stopping valve on the tool whereby the tool may be run idly at a relatively slow speed, and be immediately in creased in speedon pressing the tool against the work to handle the load suddenly placed thereon.

The invention consists further in the features ol construction and the combination oi' parts hereinafter described and claimed.

In the accompanying drawings- Fig. 1 is a longitudinal sectional view of a portable power operated impact tool embodying -a valve control of my invention and showing a lever member connecting the control rod with the laterally oi-set valve; and

Fig. 2 shows an adaptation of my invention with the valve arranged in direct line with the control rod.

The tool of Fig. l has an outer casing I containing the tool motor 2 and the impact clutch mechanism 3 as in tools of this character. The outer casing I has a. side handle 4 provided with a supply passage 5 for conveying compressed air to the tool motor 2 for rotating it. The outer end of the handle 4 has a iitting 6 whereby an air supply hose (not shown) may be connected to the tool. The handle I mounts the regular or throttle valve 'l of the tool, said valve beingy spring biased to closed position. and opened by a trigger block 8 carried by the handle. The valve 'I controls the iiow of compressed air from the 2 handle passage 5 to a supply passage B provided in the outerl casing I of the tool. The passage 9 leads to a main inlet port I0 of the porting system for the tool motor 2 and said port III is opened and closed by a spring biased valve member II in accordance with my invention.

The tool motor 2 is of the rotary type having a rotor I2 having radial blades I3 operating in slots I4. The blades I3 cooperate with a motor cylinder I5 doweled or otherwise xed against rotation in the tool case and closed at its opposite ends by end plates I6, I'l as shown in Fig. 1. The porting system of the tool follows the usual practice in this art and is such that the tool motor 2 is rotatable in reverse directions, there being a.

\ reversing valve (not shown) in the assembly for controlling this. Located in the 'forward part of the tool case I is the impact clutch mechanism 3 which in the instant showing is of the cam centrifugal type described and claimed in the Louis P. Fosnot application Ser. No. 475,377, flied February 10, 1943, now Patent No. 2,425,793, and assigned to the assignee of the instant application.

This clutch mechanism as shown herein comprises briely a rotary hammer'member I8 revolubly mounted on a shaft I9 splined or otherwise directly secured to the lower trunnion 2l of the rotor at 2I. 'I'his shaft I9 is axially alined with the rotor I2 and mounts a driving member 22 having a pair of upper and lower plates 23, 2t keyed respectively to the upper and lower end portions ci' the shaft I9 as indicated in Fig. l.

Mounted in a. diametric slot 25 in the hammer member It is a pair of siidable dogs or impact members 2B, 26 through which extend mounting pins 21, 2l. There is a pin 21 for each impact element and said pins extend through radial slots 28 in the body of the hammer member It and beyond the same into camslots 2t, 29 ot generally arcuate shape. in the plates 23. it, respectively.

Forming a part of and surrounding the clutch mechanism is an anvil member 30 in hollow cylindric shape and having a pair of axially extending jaws SI, 3I as shown. The openings between the `jaws 3i allow the impact elements 26 to move by centrifugal force into the orbital pathof the jaws to engage them in the operation of the clutch. In the rotation of the hammer member IB relatively to the anvil member 30, the impact elements 26 strike against the side edges of the .laws 3i to deliver rotational hammer blows thereto. This occurs when i'ree rotation of the anvil member 30 is arrested by engagement of the tool with the work. The anvil member 30 has a spindle 32 to journal itin the tool case l.

The impact elements 26 have impact delivery surfaces on their opposite sides and the jaws 3l at their opposite sides whereby the clutch mechanism can operate in either direction of rota- `tion of the tool mi'. The impact delivering and receiving surfaces above mentioned are substantially straight, the impact elements 23 being l0 in rectangular block-like form.

The spindle 32 is made hollow to receive and drive inthe embodiment shown in Fig. 1 the non-circular stem 33 of an adapter xture 33.

The latter extends axially below the spindle and has a flange portion 36 and a non-circular portion 36 below the same. The portion 36 is preferably square in cross-section to mount a nut or bolt head engaging socket member 31. These two parts are held in connected relation by a spring biased detent pin 38 carried by theadapter and snapping into aLhole 33 in the socket member 31. The upper stem portion 33 of the adapter is slidably retained in the spindle 32 by the pin and slot connection. the pin being marked 40 and the 25 slot 4l. The flange 35 limits the relative sliding movement between the adapter 34 and the spindle 32 when pressing the tool against the work.

In the form of my invention as shown in Fig.

1, the inlet valve Il is laterally oiset with respect to the axis of the rotor l2. The valve II is in the form of a sleeve open at both ends and receiving a coiled spring 42 for normally urging the sleeve into the closed position of the valve. against the upper end plate I6 of the motor assembly and engages at its upper end a shoulder in the sleeve Il to raise it. The upper end of the sleeve Il is provided with ports 43, 43

for admitting compressed air through the sleeve .when in open position. At this time. the sleeve Il is depressed with its upper end out of the recess in the top wall 44 of the valve housing and the compressed air may flow into the ports 33 from the main port I0.

which the valve il has movement and which side port. marked 45. is in constant register with the port ID. A port at the lower end of the valve housing is in communication with the open lower end of the sleeve il and is included in the porting system for supplying compressed air to the tool motor.

'I'he sleeve H has a stem member 46 which extends upwardly through the top wall 44 of 5 the valve housing and is pressed by the spring 32 against a lever 41 fulcrumed at 48 to the adjacent tlxed parts of the tool housing I and having an arm portion 43 extending to and bearing on the upper end of a push rod 50. 'I'he 60 latter is slidably mounted in a bore extending axially through the rotor l2 and the shaft I3 of the clutch mechanism 3 of the tool. The rod 56 is long enough to extend slightly beyond Ithe upper end of the top rotor trunnion 50a e5 of the tool motor and beyond the lower end of the clutch shaft i9 to reach and bear against the stem 33 of the adapter 34 within the spindle 32. An expansion spring 5I bears on the lever arm 49 to hold the push rod 50 against the 'Z0 adapter stem 33 as shown in Fig. 1.

The tool so far described and shown in Fig. 1 operates as follows: I have reference hereto to the opening of the sleeve valve Il by the push rod 50.

The spring 42 seats at its lower end 35 The rest of the parts operate in the 75 shown, the throttle valve 1 being the starting and stopping valve of the tool.

\/In the normal position of the parts, the adapthave complementary impact receiving surfaces 5 er 34 is held in its outwardly extended position by the action of the springs 42 and 5| on the push rod 50. On applying the tool to the work, that is, on applying the socket member 31 over the nut or bolt to be driven and pressing downwardly on the tool through its side handle 4, the adapter member 34 is forced upwardly into the spindle 32 raising the rod 33 and opening the valve Il through the lever 41. This opens the valve Il wide enough to give the added airvolume required to immediately pick up the load impressed on the tool. The

nut or bolt seats the socket 31 and'accounts for the relatively sliding movement between the adapter and the spindle on pressing the tool against the work. The bolt is marked 52 in Fig. 1.

On removing the tool from the nut or bolt, the adapter 33 movesgoutwardly by gravity and spring action and the valve il closes. The tool motor 2 idles at this time due to a small port 53 in the valve Il being in register with the inlet ports 43 and 45 to supply a small amount of air to the tool motor to keep it idling at a relatively slow speed. The rotation of the tool motor is completely stopped and started by the throttle valve 1.v

In the embodiment of my invention shown in Fig. 2, the inlet valve.is located in alinement with its actuating push rod thereby avoiding the need for the lever 41 in Fig. 1 and the expense and space incident thereto.

In Fig. 2, the inlet valve is marked Ila and is slidably mounted in a sleeve-like fixture 54 mounted in the upper end portion of the tool case 55 directly above and in axial alinement with the axis of the tool motor 2a which vis oi.' l

. ing a peripheral ilange 56 to open and close The housing for 45 the valve Il is provided with a side port over,

ports 51, 58 at opposite sides of the valve housing 54 and respectively connecting with passages 59, 60 in the tool case. to the main supply passage 3a in like manner as shown in Fig. 1.

'I'he valve 'member Huis provided with a depending stem 6| which slidably extends into a bore in the upper trunnion 62 of the tool motor 2a as shown. This bore extends axially through the rotor of the motor and also through the Isaliutch shaft in the same manner as shown in The spindle 32a, of the clutch in Fig. 2 is journalled in the tool case and is hollow to receive the upper stem portion 63 of an adapter 84. The stem portion 63 has a non-rotative connection with the spindle 32a and is xed against endwise or sliding movement therein by an intertting groove and ring arrangement as shown at 65 in Fig. 2.

The lower square portion 6B of .the adapter 64 extends below the spindle and mounts a nut or bolt engaging socket member 61 which has limited sliding movement on the adapter portion 66 and is retained in connected relation therewith by a detent pin 68 on the adapter extending into an axially elongated slot B3 in the socket member 61.

The lower stem portion 66 which mounts the socket 61 has a cross-slot 10 through which extends a cross-pin 1I. The pin 1I extends at The passage 53 leads its ends beyond the adapter stem li and mounts thereon a ring member 12. The latter bears on -the upper end of the socket member 61 and is actuating rod 13 engages the cross-pin 1| in the slot 1l which is elongated axially of the tool so that the socket member i1 in bearing fon the engaged nut or bolt lifts the socket when pressed against the work.

The push rod 1i\extends to and engages the valve stem Il so that the upward movement oi the rod in pushing down on the lool will lift the valve member Ila to open the ports 51, I to supply the increased volume of live air to the tool motor 2a to pick up the load. An expension spring 14 in the valve housing 54 above the valve member Ila normally moves the valve member towards its closed position and maintains the rod 13 against the cross-pin 1l. The valve ange 56 has an outside groove 15 in register with the ports 51, 5l to supply a limited amount of live air to the tool motor to keep it idling when the valve Il a is closed and the throttle valve is open. The upper end of the valve housing 54 is closed by a screw-cap 16 to adjust the tension of the valve spring 1l and to retain it in place.

The passage 6l in the tool case I5 leads to a port 11 which connects with the passage system of the tool for furnishing compressed air to the tool motor. The opposite sides of the impact elements 26 and of the anvil jaws 3| are provided with impact delivering and receiving surfaces, respectively, so that the clutch will function on rotating of the tool motor in opposite directions.

I may remark in passing that the clutch mechanism I within the tool serves to connect the tool motor through the hammer member I8 of the clutch to the anvil member l0 when the nut or bolt 52 is free to be driven. When the nut or bolt is not free to turn easily, as when tight, the torque of the tool motor is resisted and the clutch functions to impart a series of rotational hammer blows through the impacts of the dogs 28 against the sides of the jaws Il to further tighten or loosen the nut or bolt as the case may be.

Regardless of the form of the impact clutch mechanism with which the tool is equipped, the push rod and valve arrangement disclosed herein provides for the opening of the valve to admit a larger volume of live air to the tool motor to rotate it in accordance with the load placed thereon on applying the tool to the work whether for a nut or bolt tightening or an, unscrewing operation.

The arrangement disclosed is simple and inexpensive in construction and eiliciently performs the function for which it is designed. Moreover the arrangement disclosed provides a compact tool construction for ease in handling and manipulation.

I claim as my invention:

l. In a portable power operated impact wrench, a Huid actuated rotary motor, a rotatable spindle driven by said motor. axially shiftable socket means operatively connected with said spindle for engaging a nut to be turned, manually operable means for supplying motive fluid to the motor, an inlet valve for controlling the admission of motive fluid to the motor, said inlet valve comprising a one-piece shftable valve member and spring means normally urging said valve member to closed position, said valve member being formed with by-pass porting means for admitting a limited supply of motive uid to the motor when the valve member is in closed position whereby to permit said motor to operate at idling'speed for facilitating engagement of said socket means with the nut to be turned while said socket means is rotating at a relatively low speed. an elongated valve-actuating member extending through said spindle and said motor in axially slidable relation .therewith and operatively connected at one end thereof with said socket means, and means operatively connecting the opposite endof said valve actuating member with said valve member to eiect opening of said inlet valve whereby to admit an increased supply of motive uid to the motor for operating the latter at a relatively high nut-driving speed. said valveactuating member being axially slidable into valve-opening position in response to movement of the wrench and the socket means axially against the nut to be turned.

2. In a portable power operated impact wrench. a fluid actuated rotary motor, a rotatable spindle driven by said motor, axially shiftable socket means operatively connected with said spindle for engaging a nut to be turned, manually operable means for supplying motive fluid to the motor. an inlet valve for controlling the admission oi' motive fluid to the motor. said inlet valve comprising a one-piece shiftable valve member and spring means normally urging said valve member to closed position, said valve member being formed with by-pass porting means for admitting a limited supply of mo'tive iiuid to the motor when the valve member is in closed position whereby to permit said motor to operate at idling speed for facilitating engagement of said socket means with the nut to be turned while said socket means is rotating at a relatively low speed, and an elongated rod extending through said spindle and said motor in axially slidable relation therewith and in substantial alignment with said valve member, said rod being operatively connected at one end thereof with said socket means and being 'directly engageable at its opposite end with said valve member for opening said inlet valve whereby to admit an increased supply of motive fluid to the motor for operating the latter at relatively high nut-driving speeds. said rod being axially slidable into valve-opening position in response to movement of the wrench and the socket means axially against the nut to be turned.

3. In a portable power operated impact wrench, a fluid actuated rotary motor, a rotatable spindle driven by said motor, axially shiftable socket means operatively connected with said spindle for engaging a nut to be turned, manually operable means for supplying motive iluid to the motor. an inlet valve for controlling the admission of motive fluid to the motor, said inlet valve comprising a one-piece shiftable valve member and spring means normally urging said valve member to closed position, said valve member being formed with by-pass porting means for admitting a limited supply of motive fiuid'to the motor when the valve member is in closed position whereby to permit said motor to operate at idling speed for facilitating engagement oi' said socket means with the nut to be turned while said socket means is rotating at a relatively low speed, an elongated rod extending through said spindle and said motor in axially slidable relation therewith and operatively connected at one end thereof with said socket means, said inlet valve being opening of said inlet valve whereby to admit an e increased supply of motive iiuid to the motor for operating the latter at a relatively high nutdriving speed. said lever means being xfockable into valve-opening position upon axial sliding movementot said rod in response to movement nu 2 343.332

o1 the wrench and the socket means axially against the nut to be turned.

` GILBERT B. LARSON.

- REFERE CES CHEM The following references are of record in the ille of this patent:

n UNITED STATES PATENTS Number Name Date .1,733,542 Koehn Oct. 29. 1222 1,913,003 Shall June, 1933 2,292,146 Meunier Augfl, 1942 Shall Mar. '1. 1944 

